Low
D.17 on Vaillant Combi Compact 282EB

Your boiler has sensed that the water returning from your radiators is hotter than it should be, causing the system to temporarily throttle back its power.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description

Heating glow return regulation

DIY fix possible

Check that all radiator valves (TRVs) are fully openEnsure the central heating bypass valve is not closedCheck for any obstructions to airflow around radiatorsMonitor the boiler to see if the code clears after the system cools

Find a Gas Safe engineer
Search the official register →

Related fault codes

D.18View →

Related guides you might find useful

Radiators cold at the bottom

Sludge build-up — needs flushing, not bleeding.

Read →

Banging / kettling / whistling noise

Each noise points to a different fault.

Read →

Boiler won't turn on — 9-step checklist

Work through these before the call-out.

Read →